Dry cell and method of manufacturing the same



w. B; SCHULTE.

DRY CELL AND METHOD OF MANUFACTURING THE SAME.

APPLlCATION FILED MAY 15, 1920.

1,370,054. r v v ate ted Mar. 1, 1921.

5140M Walk/,3 0? zzZZe @513 at-toz'ncu-s UNITED STATES PATENT WALTER Z. SCHULTE, OF MADISON, WISCONSIN, ASSIGNOR TO BURGESS COMPANY, A CORPORATION OF WISCONSIN.

DRY CELL AND METHOD OF MANUFACTURING THE SAME.

' To all whom it concern! Be it known that WALTER B. SCHULTE, a citizen of the United States, residing at Madison, in the county of Dane, State of Wisconsin, have invented certain new and useful Improvements -'in Dry Cells and Methods of Manufacturing the Same; and

I do hereby declare the following to be a full," clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

The of the cathodes of such cells and to the method by which the cathodes are provided with a wrapping of bibulous material to prevent the electrode from disentegrating into the surrounding gelatinous electrolyte, but nevertheless allowing the free flow of cur- "rent to the electrode from the electrolyte.

The objects and advantages of the present invention will be made clear by the following detailed descri tion, which is to be taken in conjunction wit the accompanying drawings, wherein- Figure 1 is a' perspective view of a dry cell cathode constructed in accordance with States Patent No. 1,162,449, dated November 30, 1915, and then to compress this damp and plastic-mixture about a carbon rod to form a core or cathodefor the dry-cell. This molding of theplastic mix into cylindrical form with a carbon rod in the center may be done in suitable apparatus, as, for instance, in the tampin machine of Hambuechen United States atent No. 1,232,297,

dated July 3, 1917. The cathodes so formed,

although strong enough for manipulation on a factory basis, are-nevertheless fragile in character and subject to disintegration, particularly if their moisture content is changed substantially from that at which they are molded.

A customary way of protecting such a Specification of-Letters Patent.

Application filed May 15,

present invention relates todry-cells, bag type, and particularly to the- Patented Mar. 1,1921.

1920. Serial No. 381,652. 4

molded cathode from disentegration during the further steps in the assembly of'a complete dry-cell is to wrap the core with cheesecloth. The cheese-cloth is a fine grade, unslzed material, and in conformity with usual practice, is, held in place around the core wlth a wrapping of thread. The cloth is brought around the bottom of the core and over the top, and the thread is wound not OFFICE... I

BATTERY only around the perimeter ofthe core but also longitudinally and parallel with the carbon pencil. The wrapped core so produced can then with advantage be dip ed into a very shallow layer of melted para n to form an insulatinglayer or film across the bot:

tom, as explalned, jor'instance, in Burgess United States Patent No. 1,211,363, issued January 2,1917. The cheese-cloth is expensive and the operation of winding the wrappedcores with thread, being a hand op-" erat1on,'1s tedious and likewise expensive. Also, there is danger that through unskilled handling the soft andpla'stic cores will be deformed. Also, some of the active mixmay find its way to the outside of the cheesecloth wrapping and on assembly of the drycell be washed over into contact with the zinc, where it can produce local action with destructive results. g

In conformity with the method ofv the present invention, the bibulous envelo or wrapping for the cathode is held in p ace,

not by winding with thread, but by means of an adhesive. This method permits the use of paper inplace of cheese-cloth as the bibulous material and there is much economy not only in materials but also in labor. Likewise there is some gain in the quality of the dry-cell, as hereinafter explamed;

The papers that are most suitable for wrapping cores are good uality', thin and porous tissue papers. A shghtly calendered surface is not objectionable. The adhesive which I find most suitable is one that is thin but does not settle. A'starch, such as arrowroot, when made up in the proportions by weight of about one per cent. arrowroot in boiling water is' very satisfactory. The adhesive should have a sizing propertythat is to say, should fill the pores of the paper rather than soak through it.

The preferred mode of wrapping coresv with paper is to have the paper-cut to proper size so that an operator can easily pick up a brush or a gluing machine or roller. The i paper takes up a film of adhesive quickly and is then placed on the core and wrapped around. The operator squeezes out any air pockets which would otherwise impair the battery, and then turns over the upper and lower edges of the wrappingflo cover the top and bottom of the core. referably the paper is cut so that the grain is parallel to the axis of the electi ode when the wrapping is in place, for this reduces the danger of 1ts tearing at the corners when it is folded over at the top and bottom of the core.

The construction above described is illustrated in Fig. 1,'where 1 is the carbon rod with its brass. cap 2, and where the molded mix 3 is wrapped about with a sheet of paper 4, a fragment of which, in thedrawlng, is

illustrated as torn and folded down at 5 to diagrammatically illustrate the character of the wrapping.

The cores can now be set aside and are soon dry enough for subsequent operations. The bottom of the core may be I given a film 6 ofparafiin by dippin he core into a thin layer of melted para and'the core can then be lowered into a zinc cup, as in usual racti e, and a suitable gelatinizable paste e introduced between the zinc cup and the cathode.

Fig. 2 of the drawing shows a core properlyinstalled in its zinc container 7 with a layer of gelatinized paste intervening. This paste may consist of a mixtureof zinc.

chlorid, ammonium chlorid and a suitable cereal, such as cornstarch and water, and maybe soconstituted as to set or gelatinize a few minutes without the need for steaming or cooking, as explained, for inbe finished o stance,"in Hambuechen Patent No. 1 ,292,? 64,

datedJanuar 28,1919. The cell can then with a paraflin washer-8 and a seal 9 of pitchor sealing wax, all in conformity' with usual practice.

The salts from the electrolyte fquickly' -penetrate into and through the layer of starch adhesive, ultimately establishing equilibrium between the gelatinous electrolyte and the core, as is well understood; The

zinc vchlorid of the mix and of the electrolyte attacks the wood fiber of the bibulousj envelop, converting the paper: in part, at least, into a rubbery or parchmentized mass through which salts and moisture readily diffuse. This'assuresa path of low resistance' from the anode to the cathode, and

gives to the finished cell desirableelectrical characteristics,as will be well understood. This progressive disintegration of the paper envelop is not a disadvantage, for after complete "gelatinization of the electrolyte, the need for a bibulous envele'gf'on 'the core 'disk appear-mend the ease w the elec.-'

tricity can flow from the zinc to the car- I bonaceous cathode becomes of prime importance.

There is advantage in the present method because of its cheapness, both in labor and in material. It is possible to use a thin paper, thereby economizing in space as well as insuring the good electrical characteristics above mentioned. The mechanical operations of wrapping the core are easy. The paper only is picked. up and smeared with the adhesive, and this is easier than picking up the core and dipping it into a bath of adhesive preparator to applying the paper. There is no need or separating the cores after they have been wrapped, and while they are drying in the trays, as the adhesive does not come through the paper to any considerable extent, and the cores do not attach themselves to one another. precaution that can advantageously be kept in mind. Thevcore softens some as the result'of the application to it of the sheet of There is one paper with its moist layer'of adhesive, and

the adhesive, no manufacturing trouble is experienced.

Bibulous material other than paper, and an adhesiveiother than starch, may be employed, and various changes in the method of their use may be made, without departing from the spirit of the invention as defined bythe appended claims. I

In my application, Serial No. 381,653, filed concurrently herewith, I have described and claimed the method which consists in impregnating the cathode with an adhesive and then wrappin said cathode with a bibulous envelop w ich is secured in place by said adhesive. 1

I claim 1. A dry cell cathode of the bag type having a bibulous envelo pasted in place; substantiall as desc be 2. A ry cell cathode ofthe bag type having 'a paper envelop pasted to the top, bottom and sides of the depolarizing mix.

3. A dry cell cathode or the bag type having a pa er envelop-pasted in place with a starch a hesi've'; substantially as described.

thereto, to prevent disinte Y ,ationof themix. "into the surrounding substantially as described.

,-5. A dry cell having a, fragile mead cathode, a bibulousenvelop pastedto said latmizedelectrolyte';

cathode, and a gelatinized electrolyte surrounding said envelop; substantially as described. p

6. In the manufacture of a dry cell ofthe bag type, the step which consists in pasting a paper envelop to the cathode preparatory to addition of the electrolyte; substantially as described.

8. In the manufacture of a dry cell, the steps which consist in smearing a fiber sheet with adhesive and then wrapping and folding said sheet about the cathode mix to serve as a bibulous envelop separating. the mix from the surrounding gelatini'zed electrolyte; substantially as described.

9. In the manufacture of a dry cell, the

steps which consist in smearing a paper sheet with starch adhesive and then wrapping and folding said sheet about the cathode mix to serve as a bibulous envelop separating the mix from the surrounding gelatinized electrolyte; substantially as described.

10. In'the manufacture of a dry cell of the bag type, the steps which consist in molding WALTER B. ,SGHULTE.

' a depolarizing mix about a carbonaceous rod to form a fragile cathode, smearing a sheet .of tissue paper with starch adhesive, wrap- 

